Field of the Invention
The present invention relates to an image capture apparatus and a control method of the image capture apparatus, more particularly to a technique for assisting panning.
Description of the Related Art
Panning is a photography technique that represents a sense of speed of a moving object. The panning is a technique for obtaining images in which an object remains stationary while the background is blurred by performing image-capturing while panning the camera along with the movement of the object. In order to effectively represent the sense of speed by significantly blurring the background, it is often the case that a longer exposure time is set when panning is performed.
In order to successfully perform panning, it is important to pan the camera so as to not move the object on the imaging plane, which requires experience and techniques. Accordingly, a panning assistance function has been proposed that offsets the difference between panning velocity and object velocity by shifting the shift lens (Japanese Patent Laid-Open Nos. 2006-317848 and 2009-267834).
Japanese Patent Laid-Open No. 2006-317848 discloses a technique in which a moving object is detected based on the movement of a camera detected by a gyro sensor and the motion vectors in an image, and a shift lens is driven such that the moving object is positioned at the center of the imaging plane. However, the gyro sensor can detect only the movement in the rotating direction of the camera, and thus if a movement in the translational direction is included in panning, the blurring of the object may not be reduced sufficiently.
Japanese Patent Laid-Open No. 2009-267834 discloses a technique in which a motion vector of an object in the subsequent frame is predicted based on a temporal change (the acceleration rate) of the motion vector detected from the current frame and the previous frame, and a correction optical system is shifted so as to not move the object in the subsequent frame from its position in the current frame. However, because the acceleration rate of the object is determined based on the temporal change in the difference in position between frames, the correction accuracy decreases if the panning operation is not constant.